black smoke........

[dizzymac]

Have a '90 Cherokee 4.0. throttle was sticking, not cable....it was free. TBI was real stiff, removed from vehicle and cleaned, free now. Put back on vehicle with new gasket,torqued and connected properly. Started up....ran like crap...skips and black smoke......and exhaust is "overheating"...to the point that it scorched the carpet. Has new exhaust,including "cat"...put on same time that I cleaned TBI along with new battery. "Emission" light is on, but it was on prior to this and it ran OK. Replaced plugs yesterday, old ones in good shape except for some carbon, didn't look as though it had been on there long. Sons SnapOn analyzer says its running lean......any suggestions.....O2 maybe?....bad inj?......cold start coolant temp. sensor?.....could use help. :?
P.S. did run some carb/inj cleaner through it, was supposed to be O2 safe....hope it was.

 

[XJNick]

The 02 sensor shouldn't have any great affect on how the Jeep runs until the motor reaches normal operating temperature. It almost sounds like a timing issue to me.

-Nick :!:

 

[Tug-n-pull]

"overheating"...to the point that it scorched the carpet.

Was this the first time it ran with the new exaust? If so you may have a faulty muffler and or cat. Could be clogged or just made bad causeing it to restrict the flow! Don't see how the exaust could get that hot without a restriction in there.

skips and black smoke

Sounds like inthe cleaning process that you may hace stirred up some crud in the system. Carb cleaner and ect.. May be burning off. How long did you let it run after you put it back together?

Good luck wish I could be more help here. tug

 

[dingus]

there is a sensor on the side of the TB that is the MAP sensor... if you plugged it in upside down, it will do this. (mine did)... it has 2 little rubber prongers that plug in; one has a hole that runs to the sensor, the other plug is just to keep the vacuum tube in place. that'd be my first bet; its easy to screw that up.

 

[dingus]

PS. that tube runs up to the firewall to the actual sensor itself... it gives the computer a reading of the air pressure (should be around 18psi if i remember...) and if you have it plugged in wrong it thinks the pressure is WAAAAY higher, so it tells the fuel injectors to pump in TONS of fuel, making it run rich, which might make it overheat... mine shot out black smoke when this sensor got screwed up too...

 

[dizzymac]

...thanks for the feedback.....will check that out....checked other connections again...OK.....I do remember that I had a hell of time trying to get that back in those two holes....may not have got them all the way in....thought I did.......I do know this thing draws some serious vacuum....had it running today without the snorkel and thought it was gonna suck my hand off. this all had to start after I cleaned the TB, remember I started it after putting on new exhaust and didn't have any prob.s except throttle sticking....thats why I took it in the first place.